Strange lens

Yesterday, while down at our local camera store shopping for a strap for my new M3, I was shown a lens that is susposed to be compatible (according to the guy behind the counter) with my M3.

This is a COSMICAR 1:3.5 135MM lens made by the Ichizuka Opt. Co. It has a screw mount, but I was told a baynet adaptor could be obtained. It's about the right size and appears to be a very well made lens.

I had never heard the name in my life, but brief research reveals that the company is now owned by Pentax and makes video camera lenses. If the 135 lens you have seen is in good shape, there's no reason why it shouldn't be usable, you need to factor in $50 for an adapter of course, so the lens itself needs to be fairly cheap ($60 to 70?). If the lens needs weird-sized filters, this might be a factor against as well.

Adaptor

Originally Posted by David H. Bebbington

I had never heard the name in my life, but brief research reveals that the company is now owned by Pentax and makes video camera lenses. If the 135 lens you have seen is in good shape, there's no reason why it shouldn't be usable, you need to factor in $50 for an adapter of course, so the lens itself needs to be fairly cheap ($60 to 70?). If the lens needs weird-sized filters, this might be a factor against as well.

David,

Do you know where adaptors can be obtained? I brought the lens home (they gave it to me for $30). I thought it was worth a try, the glass appears to be in fine shape, the focus seems smooth and the appature appears to work.

If it is in M39x1 (actually x 26 tpi but everyone says x1) with the right back focus for an LTM body, then you need a female LTM-to-male M adapter. These things exist and can even be found.

If it is in T-mount (M42x0.75) you'll want a female T mount-to-male M bayonet adapter. If such things exist, they're uncommon. Female T mount-to-male M39x1 are much less uncommon, but not exactly abundant. Given one of them, you'll also need the female M39x1-to-male M bayonet adapter mentioned above.

None of these adapters gives RF coupling, so you'll have to focus by guess or tape measure and trust the lens' focused distance scale.

If the lens is in Praktica/Pentax mount (M42x1), you're probably cooked.

Following Tom's link it appears that this supplier charges $55 for an adapter (the lens will then most definitely couple with the rangefinder of your M3). Genuine Leitz/Leica adapters are harder to find (only available second-hand) and will cost the same if not more.

Your lens appears to have a screw thread at the rear. If this measures 39 mm across, you're home free (apart from needing a Leica screw-to-bayonet adapter). The T-mount system was mainly for old SLR lenses (and is now mainly for telescopes and similar devices), you could interchange an adapter at the rear of the lesn and fit it to numerous different SLRs. I have never seen a T-mount lens for Leica, they may exist, if they did they wouldn't couple with the rangefinder, but I am sure what you have is a Leica screw-thread (or Leica Thread Mount LTM) lens which will be fine for the M3 with an adapter as mentioned above.

David, FYI t-mount lenses aren't for any camera in particular, they're for all 35 mm cameras with register shorter than 55 mm, the native t-mount register. There are indeed t-mount to LTM (as in Leica thread mount, not as in Zenit SLR) body adapters, I have two of them.

To my inexperienced eye the lens looks like a t-mount, doesn't seem to have an RF cam at the rear. Oh, well.